System and method for tracking motion for generating motion corrected tomographic images

Abstract

A method and related system for generating motion corrected tomographic images includes the steps of illuminating a region of interest (ROI) to be imaged being part of an unrestrained live subject and having at least three spaced apart optical markers thereon. At least one camera is used to obtain images of the markers. Motion data comprising 3D position and orientation of the markers relative to an initial reference position is then calculated. The at least three spaced apart optical markers and the at least one camera are sufficient in quantity and position to avoid multiple epipolar solutions. Motion corrected tomographic data obtained from the ROI using the motion data is then obtained, where motion corrected tomographic images obtained therefrom.

1 . A method for generating motion corrected tomographic images, comprising the steps of:
 illuminating a region of interest (ROI) to be tomographically imaged, wherein said ROI is part of an unrestrained live subject having at least three spaced apart retro-reflective optical markers attached thereto, wherein said markers are proximate said ROI and each marker is either polarizing or depolarizing for an illuminating wavelength;   acquiring filtered optical images of said markers from at least one filtered camera, wherein a polarization filter on the at least one filtered camera enables selective detection of illumination reflected by the at least three optical markers;   calculating motion data comprising 3D position and orientation of said markers relative to an initial reference position, wherein the at least three spaced apart retro-reflective optical markers and the at least one filtered camera are sufficient in quantity and position to avoid multiple epipolar solutions; and   motion correcting tomographic data of said ROI obtained simultaneously with said motion data using said motion data, wherein motion corrected tomographic images are obtained.   
   
   
       2 . The method of  claim 1 , wherein during said method said animal is disposed in a confinement volume which is optically transparent to said illumination wavelength. 
   
   
       3 . The method of  claim 1 , wherein said tomographic images are single photon emission computed tomography (SPECT) images. 
   
   
       4 . The method of  claim 1 , wherein said illumination is aligned to be approximately coaxial with an optical axis of said first camera. 
   
   
       5 . The method of  claim 1 , wherein said illuminating is strobed illuminating. 
   
   
       6 . The method of  claim 5 , wherein said calculating motion data step comprises processing said images using a combination of segmentation, object feature extraction and digital filtering. 
   
   
       7 . The method of  claim 1 , further comprising at least a fourth spaced apart retro-reflective optical marker, wherein at least four of the markers are arranged to eliminate multiple epipolar solutions. 
   
   
       8 . The method of  claim 1 , comprising a first and a second filtered camera, wherein the acquiring step comprises acquiring simultaneous images from the first and second filtered cameras. 
   
   
       9 . The method of  claim 8 , wherein said calculating motion data step comprises processing said simultaneous images using a combination of segmentation, object feature extraction and digital filtering. 
   
   
       10 . The method of  claim 1 , comprising a first, a second, and a third filtered camera, wherein the acquiring step comprises acquiring simultaneous images of at least three of the spaced apart retro-reflective optical markers from at least two of the first, second, and third filtered cameras. 
   
   
       11 . The method of  claim 1 , wherein said illumination is polarized. 
   
   
       12 . The method of  claim 1 , wherein at least two of said markers are polarized and have different polarization characteristics. 
   
   
       13 . The method of  claim 1 , wherein at least one of the at least one filtered cameras is a video camera. 
   
   
       14 . A motion correcting tomography-based imaging system, comprising:
 at least three spaced apart retro-reflective optical markers for placement on a region of interest (ROI) to be imaged, wherein each of said markers is either polarizing or depolarizing for a wavelength produced by an illumination source;   at least one radiation detector for collecting radiation data emitted from a radioactive isotope in said ROI or radiation data provided by said ROI attenuating radiation provided by an external radiation source, and a first processor communicably connected to said radiation detector, and   structure for positioning said radiation detector relative to said ROI, and   a motion correcting system, comprising:   at least one illumination source for illuminating said ROI;   at least one filtered camera for acquiring images from said markers,   structure for positioning said at least one filtered camera; and   at least a second processor communicably connected to said first processor for calculating motion data comprising 3D position and orientation of said markers relative to an initial reference position, and motion correcting said radiation data, wherein motion corrected tomographic images are obtained from said motion correcting radiation data, wherein said system comprises at least two filtered cameras, at least four spaced apart retro-reflective optical markers, or both, in order to avoid multiple epipolar solutions.   
   
   
       15 . The system of  claim 14 , wherein said system is a single photon emission computed tomography (SPECT) system. 
   
   
       16 . The system of  claim 15 , wherein said illuminating is aligned to be approximately coaxial with at least one of said at least one filtered cameras. 
   
   
       17 . The system of  claim 16 , wherein said at least one illumination source provides strobed illumination. 
   
   
       18 . The system of  claim 17 , wherein acquisition of said images is synchronized to a strobe pulse to cause the simultaneous acquisition during an illumination period. 
   
   
       19 . The system of  claim 14 , wherein said at least one radiation detector comprises a first and a second detector. 
   
   
       20 . A method for generating motion corrected tomographic images, comprising the steps of:
 illuminating a region to of interest (ROI) to be imaged being part of an unrestrained live subject and having at least three spaced apart optical markers thereon;   acquiring optical images of said markers from at least one camera;   calculating motion data comprising 3D position and orientation of said markers relative to an initial reference position, wherein the at least three spaced apart optical markers and the at least one camera are sufficient in quantity and position to avoid multiple epipolar solutions, and   motion correcting tomographic data obtained from said ROI using said motion data, wherein motion corrected tomographic images are obtained.   
   
   
       21 . A motion correcting tomography-based imaging system, comprising:
 at least three spaced apart optical markers for placement on a region of interest (ROI) to be imaged;   at least one radiation detector for collecting radiation data from emitted from a radioactive isotope in said ROI or radiation data provided by said ROI attenuating radiation provided by an external radiation source, and a first processor communicably connected to said radiation detector, and   structure for positioning said radiation detector relative to said ROI, and   a motion correcting system, comprising:   an at least one illumination source for illuminating said ROI;   at least one camera for acquiring images of said markers, and   at least a second processor communicably connected to said first processor for calculating motion data comprising 3D position and orientation of said markers relative to an initial reference position, and motion correcting said radiation data, wherein motion corrected tomographic images are obtained from said motion correcting radiation data, wherein the system includes at least two filtered cameras, at least four spaced apart retro-reflective optical markers, or both, in order to avoid multiple epipolar solutions.